On Wed, Feb 18, 2015 at 8:53 PM, William Unruh <[email protected]> wrote:
> On 2015-02-19, Paul <[email protected]> wrote: > > On Wed, Feb 18, 2015 at 6:49 AM, Charles Elliott <[email protected] > > > > wrote: > > > >> If you don't mind me asking, why is chrony superior to NTPD > >> for tracking a PPS signal, or even in general > > > > > > Chrony (in general) pros and cons: < > > > http://chrony.tuxfamily.org/manual.html#Other-time-synchronisation-packages > > > > Just so people reading this know what you are saying > You've really got to let go of the need for third party paraphrase. *I'm* not saying anything about Chrony or Ntimed-client. The authorities on those programs should be accepted as authorities. People that want to know about Chrony can click on the link and read for themselves unfiltered by you. > > In the specific case of PPS I don't see any advantage. > > Well, no. Lichvar did some tests with PPS and found that chrony > disciplined the clock much better than did ntpd (factors of over 10). I > think that is a difference. > Do you have a link to that? The graphs I saw were all for (simulated?) clients. But it's been a while. A difference is not necessarily an advantage (I said advantage not difference) but I would have assumed that < https://github.com/mlichvar/chrony/blob/master/README> was correct which says one microsecond* (I assume offset but it's unclear) but let's go with 10x NTPd. On my machines NTPd offsets and jitter can be sub-microsecond. So the target is O(10) nanoseconds? >Note that Ntimed... > > That is a promise not fact. Lets see how it works out. If it uses the same > design > as ntpd, it is hard to see how it will "fix" the "deficiencies". But we > will see. > In fact it's a fact. Please stop refusing to read the Ntimed notes. It just makes you look bad. Besides if you read the notes you can find the glaring error and complain about it. *"With a good reference clock the accuracy can reach one microsecond." _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
